Backup NG Coherency Check

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jzzr
Posts: 3
Joined: Fri Aug 12, 2022 5:03 pm

Backup NG Coherency Check

Post by jzzr »

We want to test how to repair a corrupted Backup NG directory.

We have deleted a BLOBs item in /opt/zimbra/backup/items.
We run the command :
$ zxsuite backup docoherencycheck /opt/zimbra/backup/ accountIds zimbraId fixBackup true
Zimbra detects an error => OK

But, if we delete a metadata file in /opt/zimbra/backup/accounts/zimbraId/items
And if we run the command :
$ zxsuite backup docoherencycheck /opt/zimbra/backup/ accountIds zimbraId fixBackup true
For Zimbra all is good.

You have noticed the same operation ?
An error on our part?

Thanks

Sincerely
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L. Mark Stone
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Re: Backup NG Coherency Check

Post by L. Mark Stone »

That's an interesting test.

To my understanding the NG Backup effectively considers the contents of the accounts subdirectory as definitive.

A customer recently required disaster recovery. There was damage to the accounts subdirectory. The restore stated that there were about half the number of mailboxes available to restore than what we knew to be the case. Fortunately, we had a snapshot of the backup tree from right before the disaster, so we were able to restore the snapshot and use that to restore all of the accounts no problem.

I would also say that there is a "checkZimbra" parameter in the doCoherencyCheck command for which I have been unable to find documentation. This may be useful. Dunno. Never tested it.

You may also want to run a SmartScan with "deep true" set periodically, as this will compare what's in Zimbra to what's in the backup, and endeavor to make the backup set consistent if it is not. Recall that each night's SmartScan only checks consistency from when the last SmartScan was run.

Hope that helps.
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L. Mark Stone
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jzzr
Posts: 3
Joined: Fri Aug 12, 2022 5:03 pm

Re: Backup NG Coherency Check

Post by jzzr »

Thank you for your answer.

Only the command:

zxsuite backup dosmartscan start deep true

allows to restore the metadata file. The file is restored in the right folder of /opt/zimbra/backup/accounts/zimbraId/item

The command docoherencycheck with the option "checkZimbra true" did not work.

The dosmartscan command with the "deep true" option also allows to restore a deleted BLOBs file, the file is recreated in its original directory /opt/zimbra/backup/item

But with the dosmartscan command I could not find any log file that describes what was done. We just have a summary.

Sincerely
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